Reflective Inverse Diffusion

Phase front modulation was previously used to refocus light after transmission through scattering media. This process has been adapted here to work in reflection. A liquid crystal spatial light modulator is used to conjugate the phase scattering properties of diffuse reflectors to produce a converging phase front just after reflection. The resultant focused spot had intensity enhancement values between 13 and 122 depending on the type of reflector. The intensity enhancement of more specular materials was greater in the specular region, while diffuse reflector materials achieved a greater enhancement in non-specular regions, facilitating non-mechanical steering of the focused spot. Scalar wave optics modeling corroborates the experimental results

Measuring the Reflection Matrix of a Rough Surface

Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined for their effect on enhancement. Diffraction-based simulations were used to corroborate experimental results

Classification of personal exposure to radio frequency electromagnetic fields (RF-EMF) for epidemiological research : evaluation of different exposure assessment methods

The use of personal exposure meters (exposimeters) has been recommended for measuring personal exposure to radio frequency electromagnetic fields (RF-EMF) from environmental far-field sources in everyday life. However, it is unclear to what extent exposimeter readings are affected by measurements taken when personal mobile and cordless phones are used. In addition, the use of exposimeters in large epidemiological studies is limited due to high costs and large effort for study participants. In the current analysis we aimed to investigate the impact of personal phone use on exposimeter readings and to evaluate different exposure assessment methods potentially useful in epidemiological studies. We collected personal exposimeter measurements during one week and diary data from 166 study participants. Moreover, we collected spot measurements in the participants' bedrooms and data on self-estimated exposure, assessed residential exposure to fixed site transmitters by calculating the geo-coded distance and mean RF-EMF from a geospatial propagation model, and developed an exposure prediction model based on the propagation model and exposure relevant behavior. The mean personal exposure was 0.13mW/m(2), when measurements during personal phone calls were excluded and 0.15mW/m(2), when such measurements were included. The Spearman correlation with personal exposure (without personal phone calls) was 0.42 (95%-CI: 0.29 to 0.55) for the spot measurements, -0.03 (95%-CI: -0.18 to 0.12) for the geo-coded distance, 0.28 (95%-CI: 0.14 to 0.42) for the geospatial propagation model, 0.50 (95%-CI: 0.37 to 0.61) for the full exposure prediction model and 0.06 (95%-CI: -0.10 to 0.21) for self-estimated exposure. In conclusion, personal exposure measured with exposimeters correlated best with the full exposure prediction model and spot measurements. Self-estimated exposure and geo-coded distance turned out to be poor surrogates for personal exposure

Discriminability of tryptophan containing dipeptides using quantum control

We show that the coherent manipulation of molecular wavepackets in the excited states of trp-containing dipeptides allows efficient discrimination among them. Optimal dynamic discrimination fails, however, for some dipeptide couples. When considering the limited spectral resources at play (3nm bandwidth at 266nm), we discuss the concept of discriminability, which appears uncorrelated to both static spectra and relaxation lifetime

Past and recent effects of livestock activity on the genetic diversity and population structure of native guanaco populations of arid patagonia

Extensive livestock production and urbanization entail modifications of natural landscapes, including installation of fences, development of agriculture, urbanization of natural areas, and construction of roads and infrastructure that, together, impact native fauna. Here, we evaluate the diversity and genetic structure of endemic guanacos (Lama guanicoe) of the Monte and Patagonian Steppe of central Argentina, which have been reduced and displaced by sheep ranching and other impacts of human activities. Analyses of genetic variation of microsatellite loci and d-loop revealed high levels of genetic variation and latitudinal segregation of mitochondrial haplotypes. There were indications of at least two historical populations in the Monte and the Patagonian Steppe based on shared haplotypes and shared demographic history among localities. Currently, guanacos are structured into three groups that were probably reconnected relatively recently, possibly facilitated by a reduction of sheep and livestock in recent decades and a recovery of the guanaco populations. These results provide evidence of the genetic effects of livestock activity and urbanization on wild herbivore populations, which were possibly exacerbated by an arid environment with limited productive areas. The results highlight the importance of enacting conservation management plans to ensure the persistence of ancestral and ecologically functional populations of guanacos.Fil: Mesas, Andrés. Universidad del Bio Bio; ChileFil: Baldi, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. South American Camelids Specialist Group; Chile. Wildlife Conservation Society; ArgentinaFil: González, Benito A.. South American Camelids Specialist Group; Chile. Universidad de Chile; ChileFil: Burgi, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. South American Camelids Specialist Group; Chile. Wildlife Conservation Society; ArgentinaFil: Chávez, Alexandra. Universidad del Bio Bio; ChileFil: Johnson, Warren E.. Smithsonian Conservation Biology Institute; Estados UnidosFil: Marín, Juan C.. Universidad del Bio Bio; Chil

Transient Aplastic Crisis Caused by Parvovirus B19 Infection

O parvovírus B19 é um eritrovírus humano com tropismo para as células progenitoras da medula óssea, sendo responsável por um grande espectro de manifestações clínicas, desde infecções assintomáticas até crises aplásicas graves. Os autores apresentam o caso de uma mulher de 40 anos, com história de anemia ferropênica por menorragias, que desenvolveu quadro clínico com febre, cefaleias, petéquias e, posteriormente, exantema nas pernas, associado à hipoplasia medular com redução transitória da contagem de todas as linhagens celulares hematológicas. A suspeita de infecção aguda por parvovírus B19 foi confirmada pela detecção de anticorpos IgM antiparvovírus B19 no sangue periférico, por meio de teste imunoenzimático (ELISA). Os achados do mielograma no 5o dia após a admissão, apesar de haver ainda tão só recuperação parcial das linhagens celulares hematológicas no sangue periférico, revelaram linhagens celulares medulares normais. A paciente teve recuperação espontânea, apenas com terapêutica de suporte.info:eu-repo/semantics/publishedVersio

Thermal damping of quantum interference patterns of surface-state electrons

The temperature-dependent damping of quantum-mechanical interference patterns from surface-state electrons scattering off steps on Ag(111) and Cu(111) has been studied using scanning tunneling microscopy (STM) and spectroscopy in the temperature range 3,5-178 K. The thermal damping of the electron standing waves is described quantitatively within a simple plane-wave model accounting for thermal broadening due to the broadening of the Fermi-Dirac distributions of sample and tip, for beating effects between electrons with different kll vectors, and for inelastic collisions of the electrons, e.g., with phonons. Our measurements reveal that Fermi-Dirac broadening fully explains the observed damping for Ag and Cu. From the analysis of our data, lower limits of the phase-relaxation lengths at the Fermi energy EF Of the two-dimensional electron gas of L-phi(E-F)greater than or similar to 600 Angstrom at 3.5 K and greater than or similar to 250 Angstrom at 77 K for Ag(111), and of L-phi(E-F)greater than or similar to 660 Angstrom at 77 K and greater than or similar to 160 Angstrom at 178 K for Cu(111) are deduced. In contrast to integral measurements such as photoemission we measure L-phi close to EF and also locally. The latter eliminates residual line widths due to surface defect scattering found in the integrating techniques. Our STM results, therefore, currently provide a very good absolute estimate of L-phi and the inelastic lifetime tau=L-phi/v(F), respectively. Our values can be combined with photoemission results on dL(phi)/dT to derive the inelastic lifetime of surface state electrons at any T

Confinement of surface state electrons in Fabry-Perot resonators

Ag(111) surface state electrons have been confined in symmetric and asymmetric Fabry-Perot resonators formed by two atomically parallel step edges. The local density of states in the resonators has been measured by means of low-temperature scanning tunneling spectroscopy and can perfectly be explained with a simple Fabry-Perot-like model. The energy dependent reflection amplitudes and scattering phase shifts of the different kinds of Ag(111) step edges have been determined with high accuracy. The model character of the resonators opens up quantitative electron scattering experiments at test structures brought into the resonator